Grease two small or one large gratin dish. Preheat the oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3). Wash the sage, dab dry and remove the leaves. Peel and wash the potatoes and slice or cut them into 2 mm thin slices.
Layer with the sage like roof tiles. Season the individual layers with salt and pepper. Pour cream over them. Grate the parmesan and sprinkle half of it on top. Bake in a hot oven for about 45 minutes.
Cut off carrot green to 2-3 cm. Peel, wash and cover the carrots in
Cook in little boiling salted water for 5-6 minutes until al dente, drain. Wash the lemon hot, dry and peel the zest with a pestle ripper or peel it very thinly and cut it into fine strips. Halve the lemon, squeeze one half
Cut the pancetta into small pieces. Fry in an ovenproof pan or roasting pan without fat until crispy. Drain on kitchen paper. Chop the olives. Knead both with 2 tablespoons butter and the rest of the Parmesan cheese.
Dab fillets dry, tie in shape with kitchen string. Fry in hot frying fat for 2 minutes on each side in a pan or roasting pan. Season with pepper and a little salt.
As soon as the gratin is ready, turn down the oven temperature (electric cooker: 100 °C/circulating air and gas: not suitable). Leave the gratin in the oven to keep it hot. Continue roasting steaks in the oven for about 30 minutes.
Remove the gratin. Spread the olive mixture on the meat and gratinate under the hot oven grill for 4-5 minutes.
Meanwhile melt 1 tablespoon of butter. Roast the carrots in it. Sprinkle with 1 tbsp. sugar, caramelise and add lemon juice. Stir in lemon peel. Serve with steak and gratin.